concrete floor/damp? *pics*

[cedarnotts]

Hi,

I am due to buy a property and the survey has given results of damp in various places throughout the ground floors, kitchen, hall and lounge.
I understand now that the tool the surveyor used may not be suitable for use on concrete and have therefore kept an open mind.
The house was built in 1954 and is detatched.
It has solid ground floors which I expect are concrete and on investiagtion look to have (in the lounge) a layer of bitumen? approx 5mm.

I have rolled back carpets and found what I first thought was dust but after reflection now think it could be dormant mold?
The way the dust has formed into pattern which look just how mold would look.
The floors currently are very dry, no visable sign of damp.
The dust/mold is very dry.
I cant see any water damage to the skirting which looks old.
It looks like the property has had a lick of paint which could hide any signs of damp climbing the walls.

Please see the photos I have included and any help would be great.

http://homepage.ntlworld.com/dramatic2004/Photo-0013.jpg
http://homepage.ntlworld.com/dramatic2004/Photo-0014.jpg
http://homepage.ntlworld.com/dramatic2004/Photo-0015.jpg

Thanks in advance

 

[worms]

I think all my perfectly dry concrete floors would look a bit like that! I also get a patterned effect in the dust under the carpet on my quarry tiles and under the rug on my polished hardwood floor. I'm guessing that movement on the carpet combined with dimples on the hard surface underneath combine to form perfectly harmless patterns in the dust.

Of course others will doubtless be able to tell you more about damp concrete...

 

[davelad65]

looks like it could be dust to me also - is the underfelt damp or does it smell damp?

 

[cedarnotts]

Underlay/carpets look bone dry however it is summer.
Im concerned that come winter that the 'dust or dormant mold'
starts to kick off again.

The underlay is real thick insualtion type but the dusty substance
does not look like it could come from the underlay.
The dust is white/cream coloured (if its not clear on the pics)

thanks

 

[Moo]

The underlay seems to be one of the rubber-backed sort, so could the 'dust' be caused by condensation that's trapped under the impervious layer?

 

[cedarnotts]

The underlay seems to be one of the rubber-backed sort, so could the 'dust' be caused by condensation that's trapped under the impervious layer?

It doesnt look rubber backed but does indeed look similar to
this stuff which is rubber backed.

http://www.underlayuk.co.uk/fomalux-royale.php


I was thinking is could be trapped condensation too since I wouldnt expect damp to penetrate through the bitumen type floor surface.

Has anybody got any contacts for people who could check the problem?

Damp Proof specialists wont touch floors and only want to sell me dpc.
I need a specialist who can look at my floors and tell me if they are damp
as the survey reported.

 

[Moo]

Would it be possible for you to lift the carpet and underlay and make do with a few rugs for a while?

If the deposits don't reappear, then you won't need to pay for professional services - just the replacement of the underlay with something breathable like that lovely felt that everyone used to have. And make sure that your carpet is hessian- rather than rubber-backed.

 

[cedarnotts]

Would it be possible for you to lift the carpet and underlay and make do with a few rugs for a while?

If the deposits don't reappear, then you won't need to pay for professional services - just the replacement of the underlay with something breathable like that lovely felt that everyone used to have. And make sure that your carpet is hessian- rather than rubber-backed.

Sorry didnt explain too well.
This is on a house I am due to buy and the homebuyers survey highlighted damp in floors.
I cant try anything out unfortunatley with regards to removing carpets.
I agree that would be ideal - infact I would be happy if I knew for sure that come winter the floor will look like it is now. Bone dry
Will remember to check out hessian backed carpet.

Cheers

Thanks for the help - appreciate every response

 

[NT]

The methods of damp diagnosis used in surveys are routinely so inappropriate, and false positive dignaoses so common, that I'm not sure a survey indicating damp means much at all. The course of action I always suggest is to re-evaluate the situation, look for the usual signs of a damp problem. If there are no symptoms, there is by definition no problem.


NT

 

[cedarnotts]

The methods of damp diagnosis used in surveys are routinely so inappropriate, and false positive dignaoses so common, that I'm not sure a survey indicating damp means much at all. The course of action I always suggest is to re-evaluate the situation, look for the usual signs of a damp problem. If there are no symptoms, there is by definition no problem.


NT

I totally agree with you about no sign of damp = no damp and so have been busy snooping around the property, pulling carpets back, checking skirting board for any rot and have only come across three concerns.

1.Dust or dormat mold issue - If it is dust where has it come from?
Wierd as it doesnt seem that is would come from underlay.

2.The black bitumen / asphalt flooring seen in the pics - Is this original from 1954 or has it been put on afterwards because of a damp issue?

3.The thick carpet underlay ( i thought they had got the roof insulation mixed up with the carpet underlay
Parnoid mind asks have they used it to shield carpets from damp?

I cant see visable signs of rising damp in the walls but I think the property has recently had a cosmetic makeover (lick of paint) which
may cover any visual signs of damp in the walls.

 

[NT]

Well, I cant answer whether there is damp or not. But I can always add a few bits a long the way.

Dust under carpets is normal. Dust under rubber underlay can be dust blown up between gaps in wood floors. Dust gets everywhere anyway, and isnt a reason to diagnose a damp problem. Nor is thick underlay

Bitumen on concrete is an acceptable way to deal with a damp slab. Bitumen on wood was common long ago, though for what reason I'm not too sure.

Paint on walls can cover some black mould and stains, but normally there would be disintegration of the plaster near the wall base, and paint wont cover either that or remedial work to it.

It sounds like you cant find any evidence of damp at all.


NT

 

[cedarnotts]

The floors are solid not wood and so dust wont come through the floorboards.
Dust does get everywhere but if you look at the pics I think you must admit that if it is dust it has formed throughout the floor like mold patterns.


NT[/quote]

 

[cedarnotts]

The floors are solid not wood and so dust wont come through the floorboards.
Dust does get everywhere but if you look at the pics I think you must admit that if it is dust it has formed throughout the floor like mold patterns.

 

[worms]

While it is difficult to make out too much from the photos, I'm afraid I don't agree that this looks like mold. In my (limited) experience, concrete floors under carpets or rugs always look like this. Maybe it is just the way concrete "weathers" in the enclosed environment under a carpet. I think I would look for more serious things to worry about!

 

[Moo]

I second that.

 

[L1zzy]

I third it - if there was a major issue you would see much more evidence of it - If you had mushrooms on top of the carpet THEN be afraid!! In the mean time its quite possible that the damp thats been detected is just normal and nothing to wory about - for example I have a kitchen concrete floor I know its been poorly laid and the previous owner has just laid lino over the top - this summer it has developed an interesting 'ripple' effect - I figure that as it happened when it was ferociously hot outside its actually made the lino expand and sure enough as the weather has cooled the lino has contracted back to flat . I guess what I'm trying to say is take a chance this doesn't sound like a major worry.Hows the roof??

 

[bournonite]

Surveyors walk around with one of those protimeters and take surface damp readings - most of them are useless - they are only measuring what is in the surface, which is often only condensation which disappears when you remove the cause - closed windows, double glazing, blocked gutters etc... REAL damp is only really found by using a carbide test - drilling a small hole into the wall / stone / brick and checking whether it is damp deep inside. From the photos I'd guess not - Those floors are typically found in old council houses - if you dig through the black layer you may even find it is laid on top of the old quarry tiles, which are sometimes on soil or sometimes have a concrete base under them.... again, a trial hole with a drill will soon tell you!

Good luck

 

[Anton]

I wouldn't worry too much about it. Our house has solid floors with the bitumen top layer. It was made like that and isn't there to cure a damp problem.
Discolouration of the bitumen isn't uncommon and can be for many reasons, one of which could be as the result of a spillage having soaked through the floor coverings and stained.
the pictures aren't the best to be fair, but in the 26 years that we have lived here, we have never had any issues of damp coming up through the ground floor, and I wouldn't concern yourself unduly about it.

 

[Lime]

The pictures are what I would expect under a carpet on a solid floor.
(The type of floor you show were called "composition" floors in the 50s)
The long-gone previous carpets' mess are often left and not swept up properly when new carpet is laid. Many carpet backings deteriorate leaving behind all sorts of debris or allow dirt through from the walking surface.

Most surveys appear to reflect how much money is being borrowed. If the borrowing is near to the cost of the house the more things the surveyor will find.
This "damp" appears to be just that. A figment of the surveyor's imagination.

 

[middi]

We all know that cement floors will " choke" any respiration from the ground up, we also know it will react the same in the opposite direction.

If the cement floors have no DPM, dampness will filter into and above the concrete, this damp evaporates in the room and depending on air flow combined with reasonable amount of heat usually it is not a great problem and can be lived with.

If things auch as carpets and underlays, especially the foam or rubber backed type or even worse, types of lino or " cushion floor" are used , we would then get our own back on the cement by choking it to death.

Because any moisture will be restricted to flow neither up or down, the cement will rebel and will shed as much sweat and tears as the condition allow terminating in sweat " puddles"

Moo is right, take everything of the concreete floor, clean it and let it breathe for a while, then simply use hession backed rugs or carpets.

You can do a simple rule of thumb test before hand by simply placing a piece of carpet alongside a piece of plastic on the bare concrete for a few hours for you to notice the difference in dampness.

As to the picture, who knows.